There is a need for a rugged structure for large-area, flexible devices, in particular, for applications in switchable smart windows and outdoor information displays. In the prior art solutions include:                dispersing fluid droplets (1 to 5 microns in diameter) in a continuous polymer matrix;        microencapsulating fluid droplets and deforming them to form a monolayer of close packed polymer shells in a polymer matrix;        forming a wall structure on one substrate, coating the tops of walls with adhesive, filling the cavities between the walls with fluid, and polymerizing the adhesive to bond the tops of walls to the opposing substrate; or,        embossing a micro-cup structure onto one substrate, filling the cups with fluid having polymerizable components, and polymerizing to form a polymer skin on the fluid/cup surface.        
The prior art solutions all impose limitations and have limited suitability, typically providing a solution for one specific fluid (e.g., liquid crystal (LC)) and one specific device type (e.g. switchable LC film). All of the above solutions expose the fluid to prepolymer components and a polymerization step. This forces compromises and adds complexity. For example, the fluid components must not participate in the polymerization and the prepolymer components must phase separate from the fluid on polymerization and somehow form solid polymer structure in defined areas (e.g. only on the fluid surface of a micro-cup). Furthermore, it is difficult to develop strong chemical bonds to the surface of substrates in the presence of a fluid because the fluid will preferentially wet the surface. As a consequence it is difficult to develop strong peel adhesion in prior art devices.
The present invention provides a large-area, flexible device that does not need to expose its fluid to a polymerization step and yet has polymer structure bonded to both substrates. As described in this document, the present invention also fulfils the need for devices to have large (≥50 micron axes), self-sealed, discrete fluid volumes together with strong peel adhesion.